1. Field of the Invention
This invention relates to cleaning disks used to clean the magnetic heads in flexible disk systems. More particularly, this invention relates to cleaning disk systems which utilize thin, fibrous cleaning disks in combination with a cleaning solution to provide a wet cleaning system for the magnetic heads in a flexible disk system.
2. Description of the Prior Art
In order to achieve optimum performance and minimize maintenance requirements, it is desirable to periodically clean the magnetic heads of flexible disk systems. Unlike other peripheral devices, the magnetic heads on flexible disk drives are extremely difficult to access without partially disassembling the drive system. Due to this difficulty, head cleaning is generally done only when read/write problems are being experienced.
Several systems have been developed in an attempt to provide a convenient means of cleaning the head(s) on flexible disk systems. One such system utilizes two flexible disk jackets. One of the jackets contains an abrasive lapping material, and the other contains a cleaning cloth material. The first jacket is inserted into the flexible disk system and run through the machine for a predetermined amount of time (generally no longer than 10 seconds in order to avoid damage to the magnetic head from the abrasive material) so as to loosen debris from the head. The second jacket is then run through the machine so as to pick up the loosened debris. The jackets include standard size openings (i.e., thin radial slots) in order to allow the heads to contact the cleaning material.
A second system, described in IBM Technical Disclosure Bulletin, Volume 20, No. 8, January 1978, utilizes a standard flexible disk jacket and substitutes an abrasive disk for the normal magnetic disk. The abrasive disk is coated with either chromic oxide or aluminum oxide. The assembly is used to initially lap the magnetic heads of flexible disk drives and subsequently remove contaminant build up on the heads.
A third system for cleaning magnetic heads is disclosed in U.S. Pat. No. 4,065,798 to Sugisaki et al. This system includes a laminated disk which has a flexible nonmagnetic support (e.g., polyvinyl cloride) coated with a magnetic layer on one side and a fibrous cleaning material on the other side. The cleaning disk is located within a cartridge which contains a lubricating layer facing the magnetic layer of the cleaning disk, and includes a normal radial slit which allows the magnetic head to contact the fibrous cleaning material.
Another system is disclosed in U.S. Pat. No. 4,180,840 to Allan. This system also includes a laminated disk having an abrasive material on one side and a smooth surface on the other side. U.S. Pat. No. 4,106,067 to Masuyama et al also discloses a laminated cleaning disk.
Recently, a cleaning system has been developed which employs a nonabrasive cleaning disk made of an absorbent and porous material. The cleaning disk is typically quite thin (less than about 0.015 inches) and has a light color. The disk is carried within a jacket and is either partially or wholly saturated with a cleaning fluid. The jacket is inserted into a flexible disk system and the cleaning disk is rotated while in contact with the magnetic heads of the system. Such a system is disclosed in U.S. patent application No. 20,808 to Davis et al, filed Mar. 15, 1979, and in corresponding United Kingdom patent application publication No. 2,045,508, published Oct. 29, 1980, both of which are assigned to the same assignee as the present application.
Both magnetic media (i.e., "floppy disks") and most cleaning disks are opaque. The media or cleaning disk, as well as the jacket, contains one or more index holes. The flexible disk system includes a light source on one side of the jacket and a photodetector on the opposite side of the jacket. Normally, the opaque media or cleaning disk will interrupt light from the light source, thereby preventing the photodetector from being energized. However, as the media or cleaning disk rotates, the index hole will coincide with the path of the light source, thereby enabling the beam to strike the photodetector. The photodetector detects the transition in the amount of light received and generates a signal which signifies that a disk is in place within the system. The receipt of such a signal enables the magnetic heads to move into contact with the magnetic media or cleaning disk. As long as a transition signal is detected periodically, the head will remain engaged.
Due to the thinness and fibrous structure of the above-described Davis system, a substantial portion of light from the light source may pass through the cleaning disk, with the result being that the photodetector will not detect transitions in the amount of light received from the light source. If this occurs, the magnetic heads will be prevented from moving into contact with the cleaning disk and cleaning cannot be accomplished.